Population Dynamics and Environmental Correlates of Insect Pests in Watermelon, Citrullus lanatus (T.)

Abstract

The study was conducted in Kandavara village, Chikkaballapur district, during 2021, investigated the insect pest complex affecting watermelon, Citrullus lanatus (T) following standard crop management practices but without any insecticidal interventions to assess the natural occurrence of insect pests. Weekly observations were made from February to April (2021) employing various sampling methods to monitor key pests, including leaf miners, thrips, whiteflies, fruit flies, leaf-eating caterpillars, and pumpkin beetles. The study revealed that leaf miners, Liriomyza trifolii (Frick) were the first to appear, peaking in the 11th Standard Meteorological Week (SMW) with 6.45 leaf mines per five leaves. Thrips, Thrips palmi Karny and whiteflies, Bemisia tabaci (Gennadius) emerged during the vegetative stage, showing a significant positive correlation with maximum temperature. Fruit flies, Zeugodacus cucurbitae (Coquillett) caused the most significant damage during the fruiting stage, with a peak incidence of 14.92 per cent in the 15th SMW. The study highlighted that higher temperature had a positive correlation with pest populations, while rainfall had a negative correlation reducing the pest activity. These findings emphasize the importance of precise timing in pest management interventions to minimize crop losses and enhance the sustainability and productivity of watermelon cultivation in India.